#include <stdio.h>

int main()
{
    long ge,shi,qian,wan,x;
    scanf("ld",&x);
    wan=x/10000;
    qian=x%10000/1000;
    shi=x%100/10;
    ge=x%10;
    if(ge==wan && shi == qian)
    printf("this number is a huiwen\n");
    else
    printf("this number is not a huiwen.\n");
}